A speaker system in which sounds of a plurality of channels are emitted from a plurality of speakers, respectively, is frequently used in order to create a desired sound field when the user enjoys acoustic contents or video contents with sound in a sound space.
For example, a 2.1 channel speaker system includes not only a front left speaker (hereinafter, referred to as “Lsp”) for emitting mainly the sound of a front left channel (hereinafter, referred to as “Lch”) and a front right speaker (hereinafter, referred to as “Rsp”) for emitting mainly the sound of a front right channel (hereinafter, referred to as “Rch”) used for generating a stereo sound field but also a subwoofer (hereinafter, referred to as “SW”) for emitting the sound of a low-pitched channel (hereinafter, referred to as “LFE [low frequency effect] ch”) containing large amounts of low frequency band components.
Compared with the Lsp and the Rsp, the SW is a speaker excellent in the capability of emitting sounds in a low frequency band. Moreover, the reason why the speaker system where the SW is added to a two-channel speaker system including the Lsp and the Rsp is called a 2.1 channel speaker system is that since the frequency band where the SW can emit sound is narrow compared with the Lsp and the Rsp and the low frequency band sound emitted from the SW does not have much influence on the localization of the sound in the sound field and is poor in the independence as a channel, it is counted as 0.1.
Moreover, in recent years, for generation of a more natural sound field, a surround sound system having more channels such as 5.1 channels, 7.1 channels or 9.1 channels has been spreading.
As a technology for creating a desired sound field in a multi-channel surround sound system, for example, Patent Document 1 describes a technology where when acoustic contents including no LFEch (for example, five channels) are played back by using a speaker system including the SW (for example, 5.1 channels), in order to eliminate the delay caused with respect to the sounds emitted from the other speakers (main speakers) in the sound emitted from the SW, a delay by a delay unit is added to the pieces of audio data output to the main speakers.